In present state AoC is unfriendly for low population guilds, where many players left and only the biggest fan stayed .Would be a good idea to make a new 12 man raids.
Don't change the old ones. Leave them as they are. Just would be awesome to have 1 or 2 new raids for 12 ppl (they can be more difficult than 24 versions). It's easier to get 12 ppl than 24 especially now when there is few new ppl with subs.